Unless otherwise provided for by the governing body, the effective date of a change in the name, boundaries, or number of wards shall be the effective date of the ordinance making such change. Election of councilmembers or trustees for wards which have no representation due to such change shall take place at the time established by the governing body of the municipality but not later than the next regular municipal election. The terms of office of such new councilmembers or trustees shall be as provided for by the law applicable to the form of municipal government. A change in the boundaries or number of wards shall not disqualify a councilmember or trustee from completing the term for which he was elected.